Slit machine windup mechanism



July 12, 1960 c. 0. JENNINGS SLI'I MACHINE WINDUP MECHANISM Filed May 1, 1956 ATTORNEY r 2,944,754 Patentedduly-IZ, 1 960.

SLIT MACHINE Charles 0. Jennings, Richmoud,i-Va.;. to 7 du Pont de Nemours and Company, Del a corporation of Delaware v Filed May 1, 1955,,Se11'No. ssnm 2 Claims. (elm-tee) 1 i This invention relates to the winding of continuous being broken away to show salient features of constructio r Fig. 2 is a front elevation of the improved annular edging disc;

Fig. 3 is a cross-sectional: view on the line 3-3 of Fig. 2; and,

web and, more particularly, to improvements in apparatus for winding slit film (e.g., cellophane), paper, and the like as it comes from the slitting machine. I

One of the major defects in slit'roll formation from continuous webs of film, paper, and like pellicular struc tures is irregular'windup' produced when there is a varii aids in slit. roll formation have not entirely eliminated ifiegular p- During the slit roll windup operation; the edgesof the weaving web have'a tendencyto force (deflect-orwarp) the disc faces outward from the core upon which the slit web is being wound. This spreading of the faces causes the distance between the faces to be slightly greater than the width of the slit film. Consequently, the film edges are not in contact with both faces at any one instant, thus increasing the possibility of irregular windup. A gap between the roll endsand the'face surface of an adjacent disc is thus formed. As a result, the film can be observed to shift across this gap during windup. The shifting of the film causes variations in the roll ends which produce an irregularly wound slit roll.

An object of this invention, therefore, is to provide improved means for inhibiting irregular roll formation in the windup of continuous webs of slit film, paper, and like pellicul'ar structures. A further object is to provide improvements in apparatus for winding relatively narrow continuous webs of slit film, e.g., cellophane, as it comes from the slitting machine. The foregoing and other ob jects will more clearly appear hereinafter.

These objects are realized by the present invention which, briefly stated, comprises, in a slit roll windup mechanism comprising a driven windup mandrel, a pair of spaced rigid, annular edging discs having opposed web contacting faces and mounted on said mandrel in driving engagement therewith, and a core upon which the slit web is wound mounted on said mandrel between and in contact with said edging discs, said core being in driving engagement with said edging discs, the improvement which comprises annular edging discs the web-contacting face of at least one of said discs being recessed, the recess tapering inwardly from the outer to the inner edge of the annulus.

The invention in a preferred embodiment will now be described with reference to the accompanying drawing wherein:

Fig. 1 is a perspective view of a roll windup mechathe improved annular edging disc of this invention, parts Fig'. 4 is a taken. from Fig. 3, and

increased in scale to more clearly show the taper-recess in the edging, disc. r

Referring, to Fig. l, the slit roll windup mechanism w 3' customarily employed in the windup of slit'film, paper,

and like pellicular structures comprises: a positively driven windup mandrel 1 of a length adapted toprovide for the simultaneous windup of a plurality of. slit rolls (only one of which is shown); a hollow core 2, upon which the slit web is. wound, and annular edging discs. 3 ateach end of core '2 which serve to align the slit web as it is being wound on the core. Motion of the driven mandrel is transmitted to the core freely mounted thereon by means of a spacing sleeve 4 keyed to the mandrel which frictionally engages and thereby drives friction ring 5 bolted to the edging. disc by bolts (Fig. 2'). Outwardly projecting prongs or pins 7 (Fig. 2) in the edging discs. penetrate the wall of the hollow core and complete the driving connection between the mandrel and core.

In accordance with the present invention, the inner or web-contacting face of one or both of the edging discs is recessed, as shown in Figs. 3 and 4, toauniformly increasing depth from the outer to the inneredge of-the annulus so that. the I distance betweenv the twosweb-cont'acting faces is greater: at the'centerlie, inner edge of the annulus) between the outer edges. The max: imum distance between the edging discs (and, hence, the length of the core) corresponds substantially to the width of the split web being wound on the core.

In operation, the slit web from the slitters contacts the outer-most edge of the tapered disc faces, and since the distance between these edges is less than the width of the web and since the discs are rigid there results a slight cupping (concaving) of the web as it is guided onto the core (cf. Fig. 1), causing the web to track more uniformly on the disc faces, thus greatly reducing shifting of the web and improving the roll formation with respect to irregular windup or weave. The tapered face of the disc effectively eliminates the gap between the roll edges and the disc faces. The effect of deflected or warped edging faces is similarly reduced. Lrregularities of core ends may be compensated for by the additional recess (bevel) at the core contact point.

The degree to which the face of the edging disc is tapered to form the recess may vary in accordance with will also depend to some extent upon the physical charac- 'teristics of the web. In the winding of film, such as cellophane, a taper of 0 to has proven satisfactory. The use of a combination of a fiat-faced disc and a recessed disc may be used on small rolls, i.e., rolls 20" or less in width. However, on larger slit rolls, it is preferred that both edging discs be recessed in order to effect the best roll formation.

The edging disc having a tapered recess showed a highly significant improvement over the standard or flatfaced disc in all cases. An evaluation test was conducted during which time varying widths of slit rolls were obtained. The tapered discs and standard discs were alternated within each mill roll. The results of this test showed that there was a significant reduction in the number of irregularly wound slit rolls when the tapered discs were used. During the testing period for slit rolls under 20" in width, an 18.8% increase or a 174% improve- .ment (10.8% to 29.6%) in the number of excellent rolls and 212.6% decrease or a 21% reduction 12.I% I

to 9.5%) in the number of poor rolls was realized (see Table A); for slit rolls over 20" in width, an 8.9% increase or a 468% improvement (1.9% to 10.8% in the number of excellen rolls and a 34.2%- decrease .or a 70% reduction (49.0% to 14.8%) in the number of *poor" rolls was realized (see Table 13).

Table A TWO STANDARD DISCS vs. ONE TAPERED AND- ONE :STALNDARD DISO SLIT ROLLS UNDER 20" IN WIDTH Two Standard. Discs One Tapered One Standard Disc Grade No. Percent Grade N 0. Percent of Rolls of Rolls Excellent 41 10. 8 Excellent 103 29. 6 Very Good 225 59.2 170 48.8 G d 68 17.2 42 12.1 46 12.1 33 9.5

Table B TWO STANDARD DISCS vs. TWO TAPERED DISCS SLIT ROLLS 20" WIDE AND OVER 4 GRADING SYSTEM The roll ends extremely Iclaim: a V

1. In a windup mechanism for a slitting machine com- 7 prising a driven mandrel, a pair of spaced, annular, rigid,

edging discs mounted on said mandrel in driving engagement therewith,'a.nd a core upon which a slit web is wound mounted on said mandrel between and in driving contact with said discs, the improvement which comprises the web contacting face of at least one of said discs being recessed, the recess tapering inwardly from the outer to the inner edge of the disc whereby the distance between the-discs is greater at the inner edges thereof than at the outer edges thereof, the distance be tween thediscs being fixed and the maximum distance between the discs being not greater than the width of the slit Web being wound on the core. 1

2. A windup mechanism as in claim 1 in which both discs are recessed, each recess tapering inwardly from the outer to the inner edge of the disc.

References Cited in the file of this patent UNITED STATES PATENTS 1,469,017 Kingsbury Sept. 25, 1923 2,001,780 'Fry May 21,1935 2,015,860 May Oct. 1, 1935 1 Shlner: A single layer of film distinctly protruding beyond the adjacent layers wlthlnthe roll, so that light striking it is brightly reflected. 

